Reformed theology, specifically the doctrines of ecclesiology (church) and eschatology (last times) has from its earliest days replaced national ethnic Israel with the New Testament church.
Dispensational ecclesiology and eschatology has a simpler point of view. God does not lie. God keeps his promises to the peoples to whom he made those promises. National ethnic Israel and the New Testament church are two different peoples, with separate but intersecting destinies, whose identity is never confused, never conflated, one never substituted for the other, one never replacing the other, but always kept as two different and distinct people groups by the Holy Spirit in the Scripture. What does the Scripture say? This book answers the question through an complete exposition of Romans 9-11.